1. Field of the Invention
The present invention relates to a method for recovering olefin. More specifically, the present invention relates to a method for recovering olefin that allows continuously recovering high concentration olefin from olefin-containing gas containing olefin.
2. Description of Related Art
Heretofore, for synthesis of hydrocarbon-based polymer such as polyethylene and polypropylene, the raw materials containing olefin such as ethylene and propylene are used. In this synthesis, unreacted raw materials remain in the reaction system after the end of a synthesis reaction. Accordingly, it is attempted to recover this unreacted raw materials after the end of the synthesis reaction and reuse the recovered unreacted raw materials.
For example, Patent Document 1 discloses a gas separation method for separating hydrocarbon compound using a polymer composite membrane that is composed of a porous thin membrane made of polyolefin and filled pores in the porous thin membrane with organopolysiloxane. Patent Document 2 discloses a method for the selective separation of at least one component of a feed gas stream. The method includes passing the feed gas stream containing the component through a separation unit. The method described in Patent Document 2 employs a porous membrane that has a pore diameter of from about 10 to 200 Angstroms and where a promoter liquid containing a carrier dissolved in a suitable solvent is disposed in the pores of the porous membrane. Non-Patent Document 1 discloses a separation membrane containing silver as a separation membrane for separating gas.